ClydachGeorge wrote:
The stone is lying flat and is around 1.5 metres in diameter and around 70 cms deep. It's not quite perfectly circular, it has some small irregularities at the edges, but does have a circular hole right through its centre. It is also pretty flat across the top. I wouldn't know exactly what to look for in terms of evidence of hand working, especially given its (apparent) age and weathering - but it certainly gives the sense of having been made or cut by humans.
Sounds like a rejected millstone. From your description the central bore cut smooth for much of the centre but "punched through" the last section causing some splintering (like a circular bore through a piece of wood - without anything behind it to give it strength/ resistance to the "punch through").The central hole is interesting too: it's very circular for 75% of its depth and then somewhat less regular towards the bottom.
I've seen rejected millstones in lots of strange places. It seems it was mostly just not worth the bother of carting any broken ones or failed attempts away.
The second flat stone from the right of the group of three standing stones is a failed attempt at transforming a standing stone into a millstone...
